I have a series of Sketchup files with Text labels. Loaded one into 3D Warehouse, initial static preview looked fine.
When viewing one of these models in the viewer, the top 2/3 of all text is chopped off, leaving you only able to see the very bottom portions of letters. Zooming in and out has no impact. Prior to opening the model interactively, notice that the preview shows the full height of the text, and it is only when opened in the viewer that the Text breaks.
Can see one of these at my EverQuest website: Trials of Smoke. Default font was Tahoma 12pt, and even if changed to another, seems to have no impact.